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Nov. 4 1924.

E. E. WIGKERSHAM SPRING MOUNTED TRUCK AND CARRIER ROLLERS Filed Sept'. 5

I N VENT O R FZ'WZW'E Ww' Eens/mw wmmp, ATTO ummm BMW N WN.

E. WCKEFQSHAM SPRING MOUNTED TRUCK AND CARRIER ROLLERS Nav. 4, 1924. 1,514,181

Filed Sept. 5, 1919 2 Sheam-Shem 2 ented Novrfl, 1924.

mirtilli PATET tiFlCiil.,

ELJMER E. WICKERSHAM, ]'5 SJQCIKTON, CALIEIOBNIA, ASGIGNGR T0 Tirilli HOLT lllANU- EATURING COMPANY, OF S'IOCKTO'N, CrLIlFORNIJi.. A. CORPOltA'iN UCF CALL FORNIA.

nppleation filed lepteinhcr 3, 1919.

To IN zc/tom may concern.'

lie it known that I, Fammi: lil; Villeneusrmnf.) a citizen of the United @tati-xs, resid ing at li'tockton, `in the county ot v@an doa quin and Patate ol" Caliliornla. hare invented nec` and useful niprovein liibnnted '.llruck and Ca f which the following is a specification.

This invention relates to tractors of the chain track type and more particu]arly to a novel mountingllor the truck rollers there oit. i i

lt has for its object to cushion the truck iframe on the supporting; rollers and also to provide spring supports for the rollers which guide and support the upper rnnot track.

lfn the present case l make use ot a novel arrangeinent which permits both supporting` and carrier rollers to be spring mounted and thereby I provide not only cushions for the truck traino but also spring-pressed supports for the upper run ot the track, Where by any slack occurring in the traclu such as might be caused by yielding` ot the supporting; rollers will be taken up.

Referring; to the accomi'ianying drawings Fig. 1 shows a side elevation of the trac-- tor truck mechanism embodying' my invention.

Fig. 2 shows a sectional View taken on line .2-21 of Fig. 1.

Fig. 3 shows a cross section ot opposite truck mechanisms in connected position, supporting a main frame.

Fig. 4 shows a cross section ot truck mechanism. taken on. line 3 4: oli .Figa Il. and looliiirfii forwardly.

Fig. 5 shows a sectional View taken on line 5--5 of Fig. 3.

Fig. 6 shows a detached View in perspective of one of the supports ior the rollers.

In the :form illustrated herewith, a main `trame 1() is carried upon tractor truck mechanisins, one unit being` arranged at each side. This mechanism comprises a truck :trame on Which is journaled a series of supporting rollers 11, at the forward end of which is carried an idler sprocket Wheel 12. Ar toothed sprocket Wheel 1.3 is journaled upon the main frame and the chain track 14 is carried by the sprocket Wheels and passes beneath the rollers 11, :Forming a track lor the latter. The torni. ot truck Serial lli-ro. 321,396.

rollers are farried .thereby on a yokeshnpcd 'member 1G slidably inountci'l 'within the truck trame member and guided and heid in place therein by means ol" \\'ertirall\,' rottend.H ing ribs or rails 17'. The t 'unsrer i portion oil the yoke member 1G has a seat i :lornied thereon to receive an extensible coil s Vrice; 19 which engages at its upper end i'v'th a seat 20 termed on the inside of the i'ranie member 15. Thereby the 'weight ot the truck mechanism is supported Wholly upon the springs 1S) and since each roller is s" y connected, the said rollers are it' to yield independently.

llVithin each alternate spring` lll, which oli appreciable diameter, there is arranged a smaller coil spring` 21 coiled about a rod 22 and pressing with an `upward torce against a plate 23 liked upon said rod. The rod is slidably mounted in the` truck :trame member 15 and extends downwardly through au opening 9A in the adjacent yoke 16. Fixed upon the upper end of each rod is a roller 25 which engages the upper run of the track and serves as a support therefor.` The spring 21 acts as a. cushion :tor the roller 25 and is so adjusted as `to exert an upward force on the rod 22 and thereby maintain the track under a constant tension.

In the operation of the tractor.l it will be seen that the rollers 1]. are iree to yield in a "Vertical direction, compressing' the springs 19. This provides a cushion for theftruck mechanism, whereby all shocks and .'ioltsl caused by irregularities in the surface oit the road are absorbed. Ill? desired, the .main frame may be mounted upon the truck mechanisin Without the usual spring connections hitherto employed for cushioning the main frame.

It Will also be seen that the spring action of the carrier rollers 25 Will serve to maintain the chain track under constant tension and take up any slack occurring therein, such as results from Wear of the track or as would occur when one of the supporting` rollers 11 is depressed.

By the present arrangement of springl supports tor the supporting and carrier rollers, it will be noted th; t when one ot' the si".pliiortinp,l rollers is moved upwardly, the

v will act with increased force to move the self-laying track type, a truck frame formed* connected carrier roller 25 upwardly and thus the slack occurring in the track, due to the upward movement of the supporting roller,l will immediately be taken up by the carrier roller overhead.

Various changes in the construction and arrangement of the several parts herein shown and described may be resorted to withoutdeparting from the spirit of my invention as disclosed in the appended claims.

Having thus described vmy invention, what I claim anddesire to secure by Letters Patent is- 1. In a tractor truck mechanism of the in the shape oan inverted U,l a series of supporting rollers yfor the truck frame, a yoke for each roller slidably mounted between the side plates of the truck frame and movable vertically therein, a spring interposed between the top of the truck frame andthe transverse portion'of the yoke for supporting said truck frame yieldingly upon the'rollers,v a series of rollers for supporting the upper run of vthe track, a support for each roller'extending downwardly through the vtop of the truck frame and slidable therein, and a spring for said slidable support arranged within one of the first-mentioned springs and actiingT upon said support to press the latter upwardly, whereby to exert a yielding force against the upper run of the track and maintain the latter taut.

2. In a tractor truck mechanism of the self-laying track type, a truck frame, a chain track surrounding the same, a series of rollers on the lower portion of the truck frame to support it with relation to the chain track, spring cushioning means interposed between the rollers and the frame to permit the rollers to yield independently in passing over obstriu-tions` a second series ofi rollers on the upper portion of the truck frame, and spring cushioningr means interposed between said second series oi' rollers and the truck frame, whereby to exert a 'yielding force against the upper portion of the chain track to maintain the same taut.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

`ELMER E. IVICKERSHAM. 

